Fire damper

ABSTRACT

A folding blade fire damper is provided with a means for retaining the upper most blade, which means is integral with the damper frame. There is also provided a means for retaining the closure spring which means is integral with the frame. The method of notching out the frames to provide these means is disclosed. The spring closure is attached to the last blade of the damper in a novel manner. The blades are retained and articulated in combination with a novel connector member.

[4 1 Feb. 18, 1975 United States Patent [191 McCabe FIRE DAMPER 3 401,734 9/1968 [76] Inventor: Francis J. McCabe, Hollow Horn 3525378 8/1970 Rd., Erwinna, Pa. 18902 Sept. 12, 1973 Appl. No.: 396,392

Primary Examiner-Dennis L. Taylor [22] Filed:

ttorney, Agent, or FirmPaul & Paul ABSTRACT A folding blade fire damper is provided with a means Related US. Application Data [62] Division of Ser. No. 192,006, Oct. 26, 197], Pat. No.

for retaining the upper most blade, which means is in tegral with the damper frame. There is also means for retaining the closure sprin integral with the frame. The metlio provided a g which means is d of notching out the frames to provide these means is disclosed. The

spring closure is attached to the last blade of the damper in a novel manner.

The blades are retained and articulated combination with a novel connector member.

References Cited UNITED STATES PATENTS 2,906,323 Macy 160/68 X 2 Claims, 3 Drawing Figures r/iziiii s llllll ll Ill l/I/II/lI/Il I III/I 1 FIRE DAMPER CROSS REFERENCE TO RELATED APPLICATION This is a division of application Ser. No. 192,006, filed Oct. 26, 1971, now U.S Pat. No. 3,814,165.

BACKGROUND OF THE INVENTION This invention relates to fire dampers and more particularly to certain improvements in the frame construction of folding blade fire dampers and certain improvements in interconnection of the parts in said dampers.

In the prior art it is known to have folding blade fire dampers wherein the blades are z-shaped in section and are interconnected at the longitudinal edges by means of a sliding fit with connector members. Such a damper is disclosed in my prior patent for an Articulated Barrier U.S. Pat. No. 3,401,734. Therein, particularly as disclosed in FIGS. 1 and 2, the following arrangement of parts is shown. The blades are z-shaped in section and are notched out along the center portions of the vertical edges, so that they are arranged to have opposite blade portions on opposite sides of vertically extending inwardly depending flanges extending from the walls of the dampers. The uppermost blade is retained about a pin and is disposed on one side of the vertical flange.

The lower most blade is connected to a closure spring along the portion of the blade intermediate the web and the free end thereof. The spring is retained on a shaft extending from a flange.

SUMMARY OF THE INVENTION In the present invention improvements are made in all these features of the prior art. The upper blade is retained directly in and overlapping the central vertical side flange thereby eliminating the need for an upper support member.

The spring is mounted on a tab which is formed integrally with and extends from the wall of the damper frame. The spring is attached to the last blade in the damper at a point intermediate the web and the next adjacent connector member thereby providing for a tighter, surer closing of the damper.

An improvement is made in the connector member in that the blades are retained in their relation by the member and the coaction of the blades with the flange on both sides.

Accordingly its an object of this invention to provide an improved fire damper with less parts and better performance.

This and other objects of the invention will become apparent from the following description with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a fragmentary elevational front view of a fire damper in accordance with my invention;

FIG. 2 is the vertical central section of a fire damper taken from the left side when viewed as in FIG. 1; and

FIG. 3 is a greatly enlarged end view of a connector element DESCRIPTION OF THE PREFERRED EMBODIMENTS Although specific form of the invention have been selected for illustration in the drawings, and the followally 10 is shown. This is disclosed in my prior patent referred to above and comprises a pair of spaced upright plates 12 on each side interconnected by a top plate 14 and a base plate 15. Insofar as the disclosure of that patent would aid in understanding the disclosure in this application, said patent is incorporated herein by reference. Accordingly for the shake of simplicity all of the known parts in existing fire dampers and particularly those made in accordance with the prior patent will not be disclosed in greater detail herein. Suffice it to say that it is known to have a plurality of fan folded zshaped blades 16 which are mounted about vertically extending inwardly depending flanges 18 which extend inwardly from the sides 12. The vertical edges of the blades 16 are notched out and each of the blades is interconnected with the next adjacent blade by means of a connector 20 which is in sliding engagement along the longitudinal edges thereof for both retention and articulation.

The first improvement to the basic apparatus which I will disclose in this application is in the mounting of the uppermost blade in the damper. In accordance with the present invention I notched out the vertical inwardly extending flange 18 to form tab 22 which extends parallel the face of the flange 18 after being offset therefrom by the portion 14. The blade 17 differs from the blades 16 in that it is not notched along the vertical edges.

By way of background it is known to fabricate the frame ofa fire damper by folding a single sheet of metal into a square shape providing the configuration shown. In accordance with the present invention, as this folding operation is taking place, the web of the blade 17 is inserted into the notch in the vertical flange 18 from one side and then the other. When the frame is fully formed and closed into a box shape, the blade will be retained in the notch as illustrated. Within this notch it can be articulated as shown by the phantom lines in FIG. 2. Since the material involved is light gage metal it can easily be formed and if the tab or notch does not comfortably accomodate the blade so as to allow for articulation while at the same time providing for rentention and support, the tab can be adjusted by pliers or other suitable hand tool, said adjustment being well within the skill of one knowledgeable in the metal working art.

The next improvement to the basic damper construction which I will describe is that of eliminating the shaft and other mounting parts necessary to retain the closure spring. In accordance with my invention I have notched out the wall of the fire damper (as at 30) prior to the formation of the frame in the square shape shown. The notch consists of a relatively square shape along the intermediate portion thereof terminating in a triangular shape at the upper end. When this notch is cut the upper edge 31 of the square portion extends to undercut slightly the triangular portion. The notched out metal tab is folded at a right angle to the frame and the intermediate square portion is then rolled to form a substantially cylindrical shaped portion 32. The coiled spring 34 is placed over the cylindrical shaped tab, and, with the spring in place, the free end 36 of the tab is folded at a right angle to the cylindrical portion downward toward the end of the cylinder thereby retaining the spring on the cylindrical portion of the tab. It will be noted that ears 38 of the tab 36 will retain the spring since they are of a greater diameter than the diameter of the cylinder so formed. However they are not so great as to prevent placing of the spring about the cylinder in the first instance. In this regard the triangular shape allows for easy insertion.

I have discovered that the attachment of the spring to the last blade in a particular position can provide a unique and heretofore unkown advantage. The spring, as shown in FIG. 2 in my patent, is normally attached to the outward or lower end of the blade. This tends to leave the blade in a slightly cocked position, that is, it is not fully closed. In the present invention, by providing for attachment of the end 40 of the spring along the inner portion 42 of the last blade the forces are such that the blade closes tightly as shown. Its desirable when attaching this spring to the blade to have the position at a maximum of one-third of the blade width from the web portion 44 of the blade.

The next improvement to the basic fire damper construction which I have discovered is an improvement in the connector means. As shown in my prior patent a plurality of connectors 40 FIGS. 1 and 2 are slidingly interconnected by means of hook-shaped longitudinal edges with the edges of the blades. These connectors are free to shift laterally. Where screw heads project on the inner side of the end plates 12 it is possible for the connector elements to interfere with the screw heads. In accordance with the present invention I have cut the opposite end edges of the connector members and formed inwardly depending tabs. These tabs are formed prior to assembly. See for example the connector FIG. 1 and the greatly enlarged end view FIG. 3 which showns in greater detail the tab 21. This tab has been bent inwardly to interfer with the hookshaped channel in member 20. The cut portions are exaggerated in FIG. 1 for purposes of illustration only. The blades are then assembled from opposite sides of the connector and are retained in their assembled condition when the unit is fully assembled. In order to accomodate these tabs I have notched the inner corners of the blades (not shown). Since the blades ultimately engage the inwardly depending vertically extending flanges 18 before they engage the walls 12, these connectors will also be retained in their original lateral position without floating or interfering with the other parts of the device.

As has been alluded to above the blades with both the improved connectors and the improvement in the mounting means for the upper blade, are assembled prior to completing the assembly of the wrap-around frame. The steps in this assembly consist of sliding the blades together from alternate sides of the connectors and inserting, as an upper most blade, that blade which does not have notches in the vertical sides intermediate the edges. The uppermost blade is then inserted in the notch in the frame and the alternate blades are placed about the vertical flanges 18. The opposite side of the frame is then folded inwardly until the same relationship obtains and the corner of the frame is then connected to complete the box shaped frame.

It will be understood that various changes in the details, materials and arrangement of parts which have been herein described and illustrated in order to ex plain the nature of this invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the following claims.

It will further be understood that the Abstract of the Disclosure set forth above is intended to provide a nonlegal technical statement of the contents of the disclosure in compliance with the Rules of Practice of the US. Patent Office, and is not intended to limit the scope of the invention described and claimed herein.

What is claimed is:

1. In a fire damper having a frame and a plurality of blades interconnected for movement between a folded and unfolded condition, the improvement comprising: support means integral with said frame for retaining, supporting and permitting articulation of one of said blades, said blade being z-shaped and including a web portion; said support means comprising a plurality of flanges extending inwardly from opposite sides of said frame, each of said flanges being notched in a manner creating a tab, said notches receiving said web portion.

2. The invention of claim 1 wherein said tabs are off set from said flanges and have their free ends extending substantially parallel to said flanges. 

1. In a fire damper having a frame and a plurality of blades interconnected for movement between a folded and unfolded condition, the improvement comprising: support means integral with said frame for retaining, supporting and permitting articulation of one of said blades, said blade being z-shaped and including a web portion; said support means comprising a plurality of flanges extending inwardly from opposite sides of said frame, each of said flanges being notched in a manner creating a tab, said notches receiving said web portion.
 2. The invention of claim 1 wherein said tabs are offset from said flanges and have their free ends extending substantially parallel to said flanges. 